Dutasteride is a medication, which is somewhat similar to Finasteride (Propecia, Proscar) in that it blocks the conversion of testosterone to DHT. Finasteride blocks Type II 5-alpha-reductase and regular use of Finasteride reduces the dihydrotestosterone level by 79%. Dutasteride blocks both types of 5-alpha-reductase inhibitors. Its effect lasts in the body for up to 5 weeks and thus Dutasteride causes a more prolonged and profound effect on dihydrotestosterone levels. Currently Dutasteride is only approved for use for prostate disease. Studies for its use in hair transplantation have not been completed. There is more uncertainty about the long-term use of Dutasteride. There is no natural occurrence of men without either form of the 5-alpha-reductase inhibitors and there is not the safety data from studies about long-term use of Dutasteride. At this point, Dutasteride is not approved for treatment of hair loss. Until more is known about the effect of Dutasteride, we feel that it would be better to stick to the approved medications for the treatments for hair loss, which include, Finasteride and Minoxidil.
Ketoconazole can lower testosterone levels when taken by mouth. There is no direct proof that using topical ketoconazole reduces hair loss but, since it is used safely for other scalp conditions, some use ketoconazole shampoo regularly.